scholarly journals The vaccination of h uman beings with live avirulent vaccine of Trypanosoma cruzi: A two year follow-up of the first two cases

1972 ◽  
Vol 6 (4) ◽  
pp. 177-180
Author(s):  
Humberto Menezes
Keyword(s):  
Trypanosoma Cruzi ◽  
Large Dose ◽  
Clinical Test ◽  
Human Beings ◽  
Serological Tests ◽  
Negative Results

A two year follow-up of the first two volunteers vaccinated icith the live PF Trypanosoma cruzi strain demonstrated that the parasitological and clinical test were negative during and after that period. Of the serological tests employed, the CFT presented, in only one case, conflicting results, particulary in one laboratory and among different laboratories. However negative results were greater than all doubtful and positive one combined. The IFT icere negative in both patients. Some comments are made about the sensibility and specificity of these tests. The author concluded that the vaccine, in spite of the very large dose used in these cases, seems to be safe for human beings.

scholarly journals Etiological treatment of young women infected with Trypanosoma cruzi, and prevention of congenital transmission

2009 ◽  
Vol 42 (5) ◽  
pp. 484-487 ◽  
Author(s):  
Sergio Sosa-Estani ◽  
Estela Cura ◽  
Elsa Velazquez ◽  
Cristina Yampotis ◽  
Elsa Leonor Segura
Keyword(s):  
Trypanosoma Cruzi ◽  
Young Women ◽  
Serological Tests ◽  
Congenital Transmission ◽  
Cruzi Infection ◽  
Efficacy Of Treatment

The objective was to detect Trypanosoma cruzi infection in 32 children in Salta, Argentina, born to 16 chronically infected young women who were treated with benznidazole. Tests were performed to assess the efficacy of treatment after 14 years. At the end of the follow up, 87.5% of the women were non-reactive to EIA tests, 62.5% to IHA and 43.8% to IFA. 62.5% of the women were non-reactive according to two or three serological tests. No infected children were detected among the newborns of mothers treated before their pregnancy.

scholarly journals The Trypomastigote Small Surface Antigen from Trypanosoma cruzi Improves Treatment Evaluation and Diagnosis in Pediatric Chagas Disease

2017 ◽  
Vol 55 (12) ◽  
pp. 3444-3453 ◽  
Author(s):  
Virginia Balouz ◽  
Luciano J. Melli ◽  
Romina Volcovich ◽  
Guillermo Moscatelli ◽  
Samanta Moroni ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Surface Antigen ◽  
Rapid Assessment ◽  
Drug Efficacy ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Small Surface ◽  
Content Type

ABSTRACTChagas disease is caused by the protozoan parasiteTrypanosoma cruzi. Assessment of parasitological cure upon treatment with available drugs relies on achieving consistent negative results in conventional parasitological and serological tests, which may take years to assess. Here, we evaluated the use of a recombinantT. cruziantigen termed trypomastigote small surface antigen (TSSA) as an early serological marker of drug efficacy inT. cruzi-infected children. A cohort of 78 pediatric patients born toT. cruzi-infected mothers was included in this study. Only 39 of the children were infected withT. cruzi, and they were immediately treated with trypanocidal drugs. Serological responses against TSSA were evaluated in infected and noninfected populations during the follow-up period using an in-house enzyme-linked immunosorbent assay (ELISA) and compared to conventional serological methods. Anti-TSSA antibody titers decreased significantly faster than anti-whole parasite antibodies detected by conventional serology both inT. cruzi-infected patients undergoing effective treatment and in those not infected. The differential kinetics allowed a significant reduction in the required follow-up periods to evaluate therapeutic responses or to rule out maternal-fetal transmission. Finally, we present the case of a congenitally infected patient with an atypical course in whom TSSA provided an early marker forT. cruziinfection. In conclusion, we showed that TSSA was efficacious both for rapid assessment of treatment efficiency and for early negative diagnosis in infants at risk of congenitalT. cruziinfection. Based upon these findings we propose the inclusion of TSSA for refining the posttherapeutic cure criterion and other diagnostic needs in pediatric Chagas disease.

scholarly journals Course of Chronic Trypanosoma cruzi Infection after Treatment Based on Parasitological and Serological Tests: A Systematic Review of Follow-Up Studies

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0139363 ◽  
Author(s):  
Yanina Sguassero ◽  
Cristina B. Cuesta ◽  
Karen N. Roberts ◽  
Elizabeth Hicks ◽  
Daniel Comandé ◽  
...  
Keyword(s):  
Systematic Review ◽  
Trypanosoma Cruzi ◽  
Serological Tests ◽  
Follow Up Studies ◽  
Cruzi Infection

scholarly journals Trypanosoma cruzi: avirulence of the PF strain to Callithrix marmosets

1981 ◽  
Vol 14 (1) ◽  
pp. 73-80
Author(s):  
Humberto Menezes
Keyword(s):  
Body Weight ◽  
Trypanosoma Cruzi ◽  
Callithrix Jacchus ◽  
Blood Cultures ◽  
Serological Tests

Callithrix jacchus geoffroy marmosets (HumBol. 1812) were injected once subcutaneously with 10.000 parasites/g body weight and followed for a period of six months. The PF strain of Trypanosoma cruzi was used. Follow-up was done through blood cultures, xenodiagnosis, serological tests, and ECG. A small number of normaI animais served as control.

scholarly journals Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay

2020 ◽  
Author(s):  
Christian Irsara ◽  
Alexander E. Egger ◽  
Wolfgang Prokop ◽  
Manfred Nairz ◽  
Lorin Loacker ◽  
...  
Keyword(s):  
Disease Onset ◽  
Clinical Validation ◽  
Diagnostic Specificity ◽  
Serological Tests ◽  
Negative Results ◽  
Antibody Assays ◽  
Site Evaluation ◽  
Antibody Tests ◽  
Very High

AbstractObjectivesSerological tests detect antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the ongoing coronavirus disease-19 (COVID-19) pandemic. Independent external clinical validation of performance characteristics is of paramount importance.MethodsFour fully automated assays, Roche Elecsys Anti-SARS-CoV-2, Abbott SARS-CoV-2 IgG, Siemens SARS-CoV-2 total (COV2T) and SARS-CoV-2 IgG (COV2G) were evaluated using 350 pre-pandemic samples and 700 samples from 245 COVID-19 patients (158 hospitalized, 87 outpatients).ResultsAll tests showed very high diagnostic specificity. Sensitivities in samples collected at least 14 days after disease onset were slightly lower than manufacturers’ claims for Roche (93.04%), Abbott (90.83%), and Siemens COV2T (90.26%), and distinctly lower for Siemens COV2G (78.76%). Concordantly negative results were enriched for immunocompromised patients. ROC curve analyses suggest a lowering of the cut-off index for the Siemens COV2G assay. Finally, the combination of two anti-SARS-CoV-2 antibody assays is feasible when considering borderline reactive results.ConclusionsThorough on-site evaluation of commercially available serologic tests for detection of antibodies against SARS-CoV-2 remains imperative for laboratories. The potentially impaired sensitivity of the Siemens COV2G necessitates a switch to the company’s newly filed SARS-CoV-2 IgG assay (sCOVG) for follow-up studies. A combination of tests could be considered in clinical practice.

scholarly journals The vaccination of human beings with a live avirulent strain of Trypanosoma cruzi: a new series of volunteers

1973 ◽  
Vol 7 (2) ◽  
pp. 71-73
Author(s):  
Humberto Menezes
Keyword(s):  
Trypanosoma Cruzi ◽  
The Other ◽  
Avirulent Strain ◽  
Human Beings ◽  
Serological Tests ◽  
Human Volunteers ◽  
One Year

Five human volunteers were vaccinated with a live avirulent strain of Trypanosoma cruzi and followed-up for one year. Except for a few cases of questionable results presented by only one Laboratory, ali the other clinicai, parasitological and serological tests remained negative during that period.

scholarly journals Immunoblot Assay Using Recombinant Antigens as a Supplemental Test To Confirm the Presence of Antibodies to Trypanosoma cruzi

2007 ◽  
Vol 14 (4) ◽  
pp. 355-361 ◽  
Author(s):  
Kevin Y. Cheng ◽  
Chi-Deu Chang ◽  
Vince A. Salbilla ◽  
Louis V. Kirchhoff ◽  
David A. Leiby ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
False Positive ◽  
Test Results ◽  
Serological Tests ◽  
Assay Sensitivity ◽  
Immunoblot Assay ◽  
Recombinant Antigens ◽  
Persistent Problem ◽  
Negative Results ◽  
Positive Results

ABSTRACT The diagnosis of chronic Chagas' disease is generally made by detecting antibodies to Trypanosoma cruzi. Most conventional serological tests are based on lysates of whole parasites or semipurified antigen fractions from T. cruzi epimastigotes grown in culture. The occurrence of inconclusive and false-positive results has been a persistent problem with the conventional assays, and there is no universally accepted gold standard for confirmation of positive test results. We describe here an immunoblot assay for detecting antibodies to T. cruzi in which four chimeric recombinant antigens (rAgs), designated FP3, FP6, FP10, and TcF, are used as target antigens. Each of these rAgs is composed of several antigenically distinct regions and includes repetitive as well as nonrepetitive sequences. Each rAg is coated as a discrete line on a nitrocellulose strip. Assay sensitivity was assessed by testing 345 specimens known to be positive for antibodies to T. cruzi. All 345 of these samples showed two to four reactive test bands in addition to the three on-board control bands that are on each strip. Assay specificity was determined by testing 500 specimens from random U.S. blood donors, all of which gave negative results. Based on the results obtained in this study, we propose the following scheme for interpretation of test results: (i) no bands or a single test band = a negative result; (ii) two or more test bands with at least one band showing intensity of 1+ or higher = a positive result; and (iii) multiple faint test bands (±) = indeterminate result. Based on this scheme, the prototype immunoblot assay showed sensitivity of 100% (n = 345) and specificity of 100% (n = 500). Additionally, all 269 potentially cross-reacting and T. cruzi antibody-negative specimens tested negative in our immunoblot assay. The rAg-based immunoblot assay has potential as a supplemental test for confirming the presence of antibodies to T. cruzi in blood specimens and for identifying false-positive results obtained with other assays.

scholarly journals New Scheme of Intermittent Benznidazole Administration in Patients Chronically Infected with Trypanosoma cruzi: Clinical, Parasitological, and Serological Assessment after Three Years of Follow-Up

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
María Gabriela Álvarez ◽  
Juan Carlos Ramírez ◽  
Graciela Bertocchi ◽  
Marisa Fernández ◽  
Yolanda Hernández ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Nuclear Dna ◽  
Parasite Load ◽  
Serological Tests ◽  
Content Type ◽  
Monocyte Chemoattractant Protein 1 ◽  
Specific Antibodies ◽  
Intermittent Administration ◽  
Low Rate

ABSTRACT In a pilot study, we showed that the intermittent administration of benznidazole in chronic Chagas disease patients resulted in a low rate of treatment suspension and therapeutic failure, as assessed by quantitative PCR (qPCR) at the end of treatment. Here, a 3-year posttreatment follow-up study of the same cohort of patients is presented. The treatment scheme consisted of 12 doses of benznidazole at 5 mg/kg of body weight/day in two daily doses every 5 days. Parasite load, Trypanosoma cruzi-specific antibodies, and serum chemokine levels were measured prior to treatment and after a median follow-up of 36 months posttreatment by DNA minicircle kinetoplastid and nuclear DNA satellite sequence qPCR methods, conventional serological techniques, a Luminex-based assay with recombinant T. cruzi proteins, and a cytometric bead array. At the end of follow-up, 14 of 17 (82%) patients had negative qPCR findings, whereas three of 17 (18%) had detectable nonquantifiable findings by at least one of the qPCR techniques. A decline in parasite-specific antibodies at 12 months posttreatment was confirmed by conventional serological tests and the Luminex assays. Monocyte chemoattractant protein 1 levels increased after treatment, whereas monokine induced by gamma interferon levels decreased. New posttreatment electrocardiographic abnormalities were observed in only one patient who had cardiomyopathy prior to treatment. Together, these data strengthen our previous findings by showing that the intermittent administration of benznidazole results in a low rate of treatment suspension, with treatment efficacy comparable to that of a daily dose of 5 mg/kg for 60 days.

scholarly journals Accidental infection by Trypanosoma cruzi follow-up by the polymerase chain reaction: case report

2009 ◽  
Vol 51 (5) ◽  
pp. 295-298 ◽  
Author(s):  
Andréa Tieko Kinoshita-Yanaga ◽  
Max Jean de Ornelas Toledo ◽  
Silvana Marques de Araújo ◽  
Berenice Pelizza Vier ◽  
Mônica Lúcia Gomes
Keyword(s):  
Polymerase Chain Reaction ◽  
Trypanosoma Cruzi ◽  
Blood Smear ◽  
Fresh Blood ◽  
Chain Reaction ◽  
Negative Results ◽  
Laboratory Confirmation ◽  
Polymerase Chain ◽  
Positive Results

We report a case of accidental infection by Trypanosoma cruzi in a 42-year-old female patient who presented an inoculation chagoma. Laboratory confirmation was based on examination of fresh blood, Giemsa-stained blood smear, immunoenzyme test (EIA-IgG), indirect immunofluorescence (IIF-IgM, IgG) and polymerase chain reaction (PCR). Only the PCR gave a positive result, and the EIA test was inconclusive. Two treatments with benznidazole were necessary. PCR was the only technique that continued to give positive results for approximately two months (65 days, or 2.2 months) following the second treatment and negative results from 96 days (3.2 months) to 850 days (28.3 months). We concluded that the presence of an inoculation chagoma and use of PCR were important and decisive for diagnosis and follow-up of the case.

scholarly journals Evaluation of four commercial, fully automated SARS-CoV-2 antibody tests suggests a revision of the Siemens SARS-CoV-2 IgG assay

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christian Irsara ◽  
Alexander E. Egger ◽  
Wolfgang Prokop ◽  
Manfred Nairz ◽  
Lorin Loacker ◽  
...  
Keyword(s):  
Disease Onset ◽  
Clinical Validation ◽  
Diagnostic Specificity ◽  
Serological Tests ◽  
Negative Results ◽  
Antibody Assays ◽  
Site Evaluation ◽  
Antibody Tests ◽  
Very High

Abstract Objectives Serological tests detect antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in the ongoing coronavirus disease-19 (COVID-19) pandemic. Independent external clinical validation of performance characteristics is of paramount importance. Methods Four fully automated assays, Roche Elecsys Anti-SARS-CoV-2, Abbott SARS-CoV-2 IgG, Siemens SARS-CoV-2 total (COV2T) and SARS-CoV-2 IgG (COV2G) were evaluated using 350 pre-pandemic samples and 700 samples from 245 COVID-19 patients (158 hospitalized, 87 outpatients). Results All tests showed very high diagnostic specificity. Sensitivities in samples collected at least 14 days after disease onset were slightly lower than manufacturers’ claims for Roche (93.0%), Abbott (90.8%), and Siemens COV2T (90.3%), and distinctly lower for Siemens COV2G (78.8%). Concordantly negative results were enriched for immunocompromised patients. ROC curve analyses suggest a lowering of the cut-off index for the Siemens COV2G assay. Finally, the combination of two anti-SARS-CoV-2 antibody assays is feasible when considering borderline reactive results. Conclusions Thorough on-site evaluation of commercially available serologic tests for detection of antibodies against SARS-CoV-2 remains imperative for laboratories. The potentially impaired sensitivity of the Siemens COV2G necessitates a switch to the company’s newly filed SARS-CoV-2 IgG assay for follow-up studies. A combination of tests could be considered in clinical practice.

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